Tumor cells are known to shed nano-scale objects called circulating microvesicles (CVs) into patients' blood. These CVs have been shown to carry molecular information from the tumor, which can potentially be used to diagnose and monitor cancer using only a blood test. However, due to their extremely small size (d ~ 50 nm), there has not been a clinically viable method to detect and profile these CVs. To address these challenges, we propose a microchip-based platform that can quantitatively profile CVs directly in unprocessed whole blood. On this chip, we harness the small feature size of microelectronics and combine it with the biocompatibility of microfluidics and magnetic nanoparticles (MNPs) to measure these nano-scale objects. Our proposed device is handheld and aims to reduce measurement times from several hours using conventional equipment to less than thirty minutes. Moreover, due to the high sensitivity of our micro-magnetic sensing method, the biomarker specific limit of detection (100 CV/mL) will exceed that of conventional techniques. This innovative, clinically practical approach to CV detection has great potential for non-invasive, routine monitoring of disease progression, drug efficacy, and metastasis, offering tremendous benefits for patients.